Telegraphic system



'EL FRATTOLA, V. E. CASTELLI AND R. REGNONI.

TELEGRAPmc SYSTEM. APPLICATION FILED JAN. 25,1919.

PatentedNov. 1, 1921.

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M 1 M ff @iff @i Ey 4. Fiyi i@ i@ "c'l im Italy, and residing UNITED sTArEs @PATENT ori-ics ENRICO EEATTOLA', VITALE EGIsTo CASTELLI, ANI) RoivIUALDo REGNoNI, or ROME, 'ff ITALY.

TELEGEAPIIIC SYSTEM.

To all whom t may concern.'

, Bev it known that we, ENRICO F RATToLA, VITALE EGIsTo CASTELLI, and ROMUALDO REGNONI, all three subjects of the King of at 3 Via Rasella, Rome,

in the Kingdom of Italy, have invented certain new and useful Improvements in Telegraphic Systems, of which the following is a specification, reference being had therein to the accompanyingdrawing.

This invention relates* to means for prol tecting the instruments of a telegraphic system from the influence or disturbing effects of neighboring circuits. As an essential of the present system an alternating current of relatively high kfrequency is employed, so thatoperation maybe had when condensers aregusedl inV the circuit.

In the drawings :4

Figure l is a view showing a simple means for the protection of the telegraphic system against outside alternating* currents of low frequency. v l

Fig. 2 is a similar view showing an additionalmeans of protection.

'3- is a view illustrating a protecting means lsimilar to that of 'Fig l, superimpose'don anfordinary telegraphic circuit.

Figs. 4 and 5 illustrate afrneans in accordance with the present invention for protecting the circuit where intermediate stations are included in series.'

Figs. 6, 7, 8 and 9 indicate respectively the provision of means in a protected circuit for utilizing the vibrations of the polarized relay at the respective stations.

Fig. 10, shows a telegraphic station in accordance with the Improved system' arranged to act simultaneously with another ordinary telegraphic station. f

In Fig. l there is shown a simple means Y for protecting telegraphic circuit against the influence of outside alternating currents of low frequency, as for example, those induced by electric traction circuits with single phase or three phase currents. In this form M represents the transmission parts, R the receiving parts, C the condensers, E

the sources of the alternating current, and' L the line.

The telegraphic groups are shown in shunt on the line, and the condensers maintain the circuit insulated from the earth and impermeable to continuous currents.-A The* eil- Specifcation of Letters Patent.

Application filed January 25,1919.

.transmission ork line g Patented NOV. 1, 1921. serial ivo. 273,142.

ternatingl currents, both the operative and outside currents pass through the condensers yand receiving parts, butsuch vreceiving parts vremain inoperative to the outside currents, owing to their low frequency.

In protecting against outside currents whichmay reach a high value, it is contemplated that the line be grounded at various points through inductive resistances I which should `be practicably impermeable to the currents, while permitting the passage through them of large quantitieg of outside currents.

r The simple Acircuit of Fig. l' may evidently vbe superimposed onthe conductor of an ordinary telegraphic circuit, and work simultaneously with the latter. This is illustrated in Fig. l8 wherein the circuit of Fig. 1 is shown as applied to the ordinary telegraphic circuit including 'the ordinary .telegraphic groups T. l

The receiving group consists of a polarized relay of any desired'type which is connected in series witha small capacity, `the whole being in shunt between the line conductor and the earth. The relative values of relay inductance and capacity in series are chosen so that -for the frequency of the current ,employed theyare nearer the resonance thanvthe frequency ofA `the f outside currents. As an infinite numberofycouples of these values meet the desired result, it is possible to choose foreach particular case that one which affords the necessary obstruction to the low frequencyoutside currents.

Therefore the new system will thus reduce to any desired extent the value of the outside currents in the receiving arrangement. When intermediate stations are to be included in series instead of in shunt, the in- 'ductance and the effective resistance of the vibration of thearmature of the polarized relay closes a local circuit at intervals, which circuit is of low self induction an includes a battery P1, and a second relay R2, constructed so as to keep the circuit of the instrument continually closed during the time that the battery supplies intermittent current. Y

In Fig. 7 the armature vibrations of the polarized relay renders intermittent a contact which when at rest is closed. The lack of continuity in this contact amounts to an increase of its resistance, and this produces the working of the instrument which has a differential winding, as indicated at A. In Fig. 8 the instrument is connected to divide the current into two circuit loops, each of which includes an inductive resistance. These resistances are such that there is ordinarily no differences of potential between the points of connection and the instrument. In' the vibration of the armature'of the polarized relay however the resistance of one of the loops is increased, and the instrument records the signal. i M

In Fig. v9 the cores or armatures of the electromagnet of'the instrument are polarized so'that Athearmature would normally be attractive. The current supplied -by the battery P to the circuit holds the armature open, vso that the recording apparatus A will register each or when the current resistance is increased. Obviously, in lieu of polarizing thev` instrumenta second polarized relay may be placed soas to close the circuit ofthe instrument. *If ig. 10 shows the completed construction for a telegraphic station of the present'system, to act simultaneously with an ordinary telegraphic station. A telegraphic machine 'is controlled by the polarized relay and an intermediate common relay. The transmission 'group comprises an time the current'is interrupted A ordinary vi- Y brator induction coil and transmission may be effected by a five contact key.

rIhe transmission group comprises a source of alternating current of the `desired value and frequency, and having in series therewith a condenser of suitable capacity, which is also in correspondence with the electric constants of the circuit.

What is claimed as new is: Y

A system adapted to telegraphic lines for receiving` purposes where such lines use alternating currents of relatively high frequency and are exposed to perturbation currents from electric traction lines and the like, Asaid system comprising in `substantial resonance with the line, a polarized relay of great inductance and a condenser of low capacity in series with said relay, wherebyV there' is presented a strongy obstruction to perturbation currents.

VInwitn'ess whereof, said ENnIoo FRA'rroLA has signed this Vspecification at Rome, this 21st day of December, 1918."V

, ENRICO FRATTOLA.

' Inthe vpresence ofA Y GIOVANNI PUGGI,

. LUIGI EMELIAN.

In witness whereof, said VITALE EeIs'ro CASTELLI has signed this specification. at

Rome, Italy, this 21stA day of December,

1918. A i Y VITALE EGISTO, CASTELLI.l In presence of#- Y GIOVANNI PUooI, LUIGI EMELIAN.

Italy, Y

In witness whereof, said RoMUALDo REG- l NoNI'has signed thisspecification at Rome, Italy, this 21st' day of December', 1918.

Y y liRQMUALDO REGNONI. In the presence of-vl Y i Y vGIOVANNI PUCGI,

' LUIGI EMELIAN. 

